title: Notch3 inhibition enhances sorafenib cytotoxic efficacy by promoting GSK3b phosphorylation and p21 down-regulation in hepatocellular carcinoma.
abstract: Sorafenib (Nexavar), a multiple kinase inhibitor, is the only clinically approved drug for patients with advanced HCC. However, its therapeutic success is limited by the emergence of drug resistance. Here we found that p21 and pGSK3βSer9 are major players in the resistance to sorafenib. We recently reported that aberrant Notch3 expression in HCC contributes to doxorubicin resistance in vitro and, therefore, we focused on the mechanisms that associate Notch3 to acquired drug resistance. In this study we first found that Notch3 inhibition significantly increased the apoptosis inducing effect of sorafenib in HCC cells via specific down-regulation of p21 and up-regulation of pGSK3βSer9. Using a mouse xenograft model we further found that Notch3 depletion combined with 21 days of sorafenib treatment exerts a substantial antitumor effect in vivo. Interestingly, we showed that, upon exposure to sorafenib treatment, Notch3 depleted xenografts maintain lower levels of p21 and higher levels of pGSK3βSer9 than control xenografts. Thus, this study demonstrated that inhibition of Notch3 signaling prevents HCC-mediate drug resistance and sensitizes HCC cells to sorafenib. Finally, we validated our in vitro and in vivo results in primary human HCCs showing that Notch3 protein expression positively correlated with p21 protein expression and negatively correlated with pGSK3βSer9 expression. In conclusion, the results presented in this study demonstrated that Notch3 silencing enhances the effect of sorafenib by overcoming drug resistance. Notch3 inhibition in combination with sorafenib can be a promising strategy for treatment of HCC.
authors.affiliation: Center for Applied Biomedical Research (CRBA), S.Orsola-Malpighi University Hospital, Bologna, Italy.
authors.forename: Catia
authors.initials: C
authors.lastname: Giovannini
authors.forename: Michele
authors.initials: M
authors.lastname: Baglioni
authors.forename: Marco
authors.initials: M
authors.lastname: Baron Toaldo
authors.forename: Cristiano
authors.initials: C
authors.lastname: Ventrucci
authors.forename: Stefania
authors.initials: S
authors.lastname: D'Adamo
authors.forename: Mario
authors.initials: M
authors.lastname: Cipone
authors.forename: Pasquale
authors.initials: P
authors.lastname: Chieco
authors.forename: Laura
authors.initials: L
authors.lastname: Gramantieri
authors.forename: Luigi
authors.initials: L
authors.lastname: Bolondi
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D004357:Drug Synergism; D005260:Female; D055785:Gene Knockdown Techniques; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D010671:Phenylurea Compounds / Q000494:pharmacology*; D010766:Phosphorylation; D000071656:Receptor, Notch3; D051880:Receptors, Notch / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D000077157:Sorafenib; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; C499374:NOTCH3 protein, human; D010671:Phenylurea Compounds; D000071656:Receptor, Notch3; D051880:Receptors, Notch; D009536:Niacinamide; D000077157:Sorafenib; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3